Foster T J, Lundblad V, Hanley-Way S, Halling S M, Kleckner N
Cell. 1981 Jan;23(1):215-27. doi: 10.1016/0092-8674(81)90286-5.
We describe three related DNA alterations associated with transposon Tn10: precise excision of Tn10, nearly precise excision of Tn10 and precise excision of the nearly precise excision remnant. DNA sequence analysis shows that each of these alterations results in excision of all or part of the Tn10 element, and each involves specific repeat sequences at or near the ends of the element. Furthermore, all three events are structurally analogous: in each case, excision occurs between two short direct-repeat sequences, with resulting deletion of all intervening material plus one copy of the direct repeat; and in all three cases, the direct repeats involved occur at either end of an inverted repeat. Analysis of mutant Tn10 elements and characterization of bacterial host mutations suggest that all three types of excision events occur by pathways that are fundamentally distinct from the pathway(s) for Tn10-promoted transposition and other DNA rearrangements (deletions and inversions) actively promoted by the element. In addition, precise excision and nearly precise excision appear to occur by very closely related or identical pathways; and several lines of evidence suggest that the 1400 bp inverted repeats at the ends of Tn10 may play a structural role in both of these events. The third excision event appears to occur by yet another pathway.
我们描述了与转座子Tn10相关的三种相关DNA改变：Tn10的精确切除、Tn10的近乎精确切除以及近乎精确切除残余物的精确切除。DNA序列分析表明，这些改变中的每一种都会导致Tn10元件全部或部分被切除，并且每种改变都涉及元件末端或其附近的特定重复序列。此外，所有这三种事件在结构上是相似的：在每种情况下，切除都发生在两个短的直接重复序列之间，导致所有中间物质以及一个直接重复拷贝被删除；并且在所有三种情况下，所涉及的直接重复序列都出现在反向重复序列的两端。对突变型Tn10元件的分析以及细菌宿主突变的表征表明，所有这三种切除事件发生的途径与Tn10促进转座的途径以及该元件积极促进的其他DNA重排（缺失和倒位）的途径根本不同。此外，精确切除和近乎精确切除似乎通过非常密切相关或相同的途径发生；并且有几条证据表明，Tn10末端的1400 bp反向重复序列可能在这两种事件中都发挥结构作用。第三种切除事件似乎通过另一种途径发生。
